MacArthur, R-3rd Dist., spent $59,601 from January to June on mailings and printing, according to filings with the Clerk of the House. The other 11 House members from the Garden State spent a combined total of $32,775.

Known as "franking," each member can use taxpayer funds to communicate with voters, often by newsletters sent to residents of their districts.

The campaign manager for MacArthur challenger Andy Kim called the spending "shameful."

"Why is Tom MacArthur, a multi-millionaire with backing from Goldman Sachs and Exxon, abusing so much of our hard-earned tax dollars on self-promotion?" Kim campaign manager Zack Carroll said.

Freshman Rep. Josh Gottheimer, D-5th Dist., facing a tough 2018 re-election campaign, was second in spending with $7,606. Rep. Albio Sires, D-8th Dist., who occupies a safe seat, was the most frugal with just $886 in expenditures.

Both MacArthur and Gottheimer spent funds on tele-town halls, where they took questions via telephone from constituents, filings show. The process involved making automatic phone calls to residents to invite them to connect to the event, or to leave a message if no one answered.

After the House vote on health care, the Cook Political Report, a Washington-based publication that tracks congressional races, rated MacArthur as more vulnerable though still a strong favorite for re-election.

Through Sept. 30, MacArthur doubled his fundraising to $1.2 million from the $610,826 he brought in during the same period two years earlier. Trump hosted June fundraiser for him at the president's Bedminster golf club that brought in $367,931 for his campaign committee.

Kim, a former White House national security adviser, raised $255,187. That was 425 times more than MacArthur's last Democratic challenger, Frederick John LaVergne, brought in for his entire campaign.

Kim also picked up the support of two progressive groups with donor networks that contribute to endorsed candidates.